1. Field
This invention concerns a unique pumping device for fluids, including gasses, of any type, and particularly concerns a lubricating oil pumping system or mechanism for work devices which are driven by drive shafts, including refrigeration compressors, pumps, or the like, particularly where the pumping system is associated with the drive shaft and wherein said shaft is driven by an electrical motor or other prime mover which is reversible in rotation, either intentionally or unintentionally.
Such work devices are shown, for example, in U.S. Pat. Nos. 4,479,419; 4,236,874; 4,494,447; 4,245,996; and 4,248,053, the disclosures of which are hereby incorporated herein by reference, in their entireties, and in pending U.S. application Ser. No. 09/133,841 filed Aug. 13, 1998; and Ser. No. 09/013,154 filed Jan. 26, 1998, the disclosures of which are hereby incorporated herein by reference in their entireties, and which applications are commonly owned with this present application. In these disclosures intentionally reversing direction of the drive motor causes one or more pistons to be fully or partially taken off line to thereby reduce the compressor capacity. Another such work device is the conventional refrigeration compressor which, for example, might use a three phase motor wherein, if the electrical connections are not properly made, the motor and drive shaft will rotate oppositely to what was intended.
In such situations described above, the lubricating oil pump, whatever its construction may be, must be able to deliver sufficient lubricating oil to compressor shaft bearings, wrist pin bearings and the like regardless of the direction of motor rotation.
2. Prior Art
Heretofore various and complicated lubricating oil pump mechanisms have been proposed for such rotationally reversible applications as disclosed in U.S. Pat. Nos. 4,331,421; 4,331,420; 3,418,939; and 2,855,139. These mechanisms tend toward complex construction and valving, and, particularly from the perspectives of longevity, reliability, ease of manufacture and costs, are lacking.
A principal object therefore of the present invention is to provide a low cost, extremely simple, self-priming reversible oil pump structure which will pump in the same direction regardless of direction of rotation, and having extraordinary performance and longevity reliability, and being especially adapted for use in refrigerant compressors.
The above and other objects hereinafter becoming evident have been attained in accordance with the present invention thru the discovery of unique structure for pumping fluids, which in one preferred embodiment of use is in a gas compressor having body or crankcase means, a drive shaft rotatably supported on said body means and connected to and adapted for operating compression generating structure of the compressor, said shaft having a rotational axis and being connected to electrical motor means for being driven thereby in either rotational direction, oil passage means formed in said shaft generally longitudinally thereof for conveying lubricating oil to various portions of said compressor, at least one slot formed generally laterally thru a portion of said shaft and communicating with said oil passage means, said slot having an elongated vane slidably mounted therein for functional movement both longitudinally and laterally of the slot but not vertically such as to provide thereby oil conduit means alongside said vane regardless of the direction of rotation of said shaft and regardless of the position of said vane in said slot, wall means slidably enclosing said shaft portion and contiguous portions of said shaft and having a circular inner surface section eccentrically positioned with respect to said rotational axis of said shaft such that a small vertical peripheral segment of said inner surface lies adjacent said shaft portion to thereby provide a generally crescent shaped pumping chamber between said shaft portion and said inner surface, and oil inlet means provided thru said wall means and communicating with said pumping chamber.
In certain preferred embodiments:
(a) the section of said oil passage means which lies within said portion of said shaft is substantially axial of said shaft and two slots are provided and are formed on the same diameter of said shaft;
(b) said segment and said inlet means are on substantially the same diameter of said shaft and on diametrically opposite sides thereof;
(c) said oil passage is coextensive with said slots at said rotational axis;
(d) for the embodiment of (a) hereof, the ratio of the volume in in3 of said pumping chamber to the flow area in in2 of said oil conduit means is from about 1.11 in. to about 1.38 in.;
(e) with reference to (d) above, said oil passage is a circular bore having a diameter of from about 0.15 to about 0.25 in; and
(f) said wall means is formed in a lower bearing means affixed to the crankcase and which supports said drive shaft both laterally and longitudinally thereof.